As a third generation (3G) wireless access method for cellular mobile communication, W-CDMA (Wideband Code Division Multiple Access) has been standardized by the 3GPP (3rd Generation Partnership Project), and cellular mobile communication services using W-CDMA has been provided. Additionally, evolved universal terrestrial radio access (hereinafter, referred to as “E-UTRA”) and evolved universal terrestrial radio access network (hereinafter, referred to as “E-UTRAN”) have been considered by the 3GPP.
OFDM (Orthogonal Frequency Division Multiplexing), which is a multi-carrier transmission scheme, has been proposed for an E-UTRA downlink that is transmission from a base station device to a mobile station device. Additionally, DFT-Spread OFDM (Discrete Fourier Transform-Spread OFDM), which is a single-carrier transmission scheme, has been proposed for an E-UTRA uplink that is transmission from a mobile station device to a base station device.
In E-UTRA, a base station device BS1 performs wireless communication with mobile station devices UE1, UE2, and UE3. The E-UTRA downlink, which is wireless communication from the base station device BS1 to the mobile station devices UE1, UE2, and UE3, includes a downlink pilot channel, a downlink synchronization channel, a broadcast channel, a downlink control channel, a downlink shared data channel, a control format indicator channel, a downlink HARQ (Hybrid Automatic Repeat reQuest) indicator channel, and a multicast channel. The E-UTRA uplink, which is wireless communication from the mobile station devices UE1, UE2, and UE3 to the base station device BS1, includes an uplink pilot channel, a random access channel, an uplink control channel, and an uplink shared data channel.
<Unicast Sub-Frame>
FIG. 15 illustrates a schematic structure of an E-UTRA downlink radio frame (section 6.2 of Non-Patent Document 1). FIG. 15 illustrates, as an example, a schematic structure of a unicast sub-frame in a radio frame upon time-multiplexing of the downlink control channel and the downlink shared data channel. The horizontal and vertical axes shown in FIG. 15 denote time and frequency axes, respectively. The downlink radio frame includes multiple PRB (Physical Resource Block) pairs. The PRB pair is a unit of a radio resource assignment and the like for localized transmission and is defined by a frequency band (PRB bandwidth) and a time band (2 slots=1 sub-frame) which have predetermined widths.
Basically, one PRB pair includes two consecutive PRBs (PRB bandwidth×slot) in the time domain.
Regarding a sub-frame in which the downlink control channel and the downlink shared data channel are time-multiplexed (hereinafter, referred to as a “unicast sub-frame”), one PRB includes 12 subcarriers in the frequency domain and 7 OFDM symbols in the time domain. A system bandwidth is a communication bandwidth of the base station device. In the time domain, a slot includes 7 OFDM symbols, a sub-frame includes two slots, and a radio frame includes 10 sub-frames.
A unit defined by one subcarrier and one OFDM symbol is referred to as a resource element. In the downlink radio frame, multiple PRBs are allocated in the frequency direction according to the system bandwidth. A structure of an MBSFN sub-frame (Multicast/Broadcast over Single Frequency Network Sub-frame, hereinafter referred to as “multicast sub-frame”), in which a multicast channel in lieu of the downlink shared data channel is time-multiplexed with the downlink control channel, will be explained later.
At least the downlink shared data channel for transmitting information data and system information and the downlink control channel for transmitting control data are allocated to each unicast sub-frame.
The system information includes information required for the base station device and the mobile station device to communicate with each other. The system information is periodically transmitted to an unspecified number of mobile station devices on the broadcast channel and the downlink shared data channel. Items of system information allocated to the broadcast channel differ from those allocated to the downlink shared data channel. The system information allocated to the broadcast channel includes a system bandwidth, setting information of the downlink HARQ indicator channel, the number of transmit antennas, and the like. The system information allocated to the downlink shared data channel includes uplink and downlink transmit power control information, setting information of sub-frames for neighbor base station devices, setting information of a sub-frame for the base station device (serving base station device), and the like.
The downlink pilot channel for channel estimation of the downlink shared data channel and the downlink control channel is not illustrated in FIG. 15, and allocation thereof will be explained later. FIG. 15 shows a case where the downlink control channels are allocated to the first, second, and third OFDM symbols, which are counted from the starting position of a sub-frame, and the downlink shared data channels are allocated to other OFDM symbols. The number of OFDM symbols, to which the downlink control channels are allocated, varies in units of sub-frames.
Although not shown in FIG. 15, the control format indicator channel, which indicates the number of OFDM symbols forming the downlink control channels, is allocated to a predetermined frequency position of the first OFDM symbol. The downlink control channel is allocated to only the first OFDM symbol in one case, to the first and second OFDM symbols in another case, to the first to third OFDM symbols in another case, or the like. Allocation of the control format indicator channel will be explained later. Similarly, although not shown in FIG. 15, the downlink HARQ indicator channel is allocated to an OFDM symbol to which the downlink control channel is allocated. In other words, the downlink HARQ indicator channel is frequency-multiplexed with the downlink control channel. The downlink control channel and the downlink shared data channel are not allocated to the same OFDM symbol. Multiple pieces of uplink radio resource assignment information, downlink radio resource assignment information, transmit power command information, and the like are allocated to the downlink control channels in the unicast sub-frame. The details of information allocated to the downlink control channel will be explained later.
<Pilot Channel in Unicast Sub-Frame>
FIG. 16 illustrates allocation of the downlink pilot channels included in one PRB pair in an E-UTRA downlink unicast sub-frame (section 6.10.1 of Non-Patent Document 1). The horizontal and vertical axes shown in FIG. 16 denote time and frequency axes, respectively. A case where the base station device has four transmit antennas (a transmit antenna 1, a transmit antenna 2, a transmit antenna 3, and a transmit antenna 4) is explained here. A resource element assigned reference numeral R1 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 1. A resource element assigned reference numeral R2 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 2. A resource element assigned reference numeral R3 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 3. A resource element assigned reference numeral R4 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 4.
When the base station device has only two transmit antennas, the downlink control channels are transmitted on the resource elements R3 and R4 in the second OFDM symbol. The downlink shared data channels are transmitted on the resource elements R3 and R4 in the ninth OFDM symbol.
The broadcast channel and the downlink synchronization channel have little relation to the present invention, and therefore detailed explanations thereof are omitted here. However, the broadcast channel and the downlink synchronization channel are allocated to a predetermined resource element in a predetermined sub-frame.
<Structure of Multicast Sub-Frame>
FIG. 17 illustrates a schematic structure of a multicast sub-frame in the E-UTRA downlink (section 6.5 and 6.10.2 of Non-Patent Document 1). The horizontal and vertical axes shown in FIG. 17 denote time and frequency axes, respectively. In the multicast sub-frame, one PRB includes 12 subcarriers in the frequency domain and 6 OFDM symbols in the time domain. In the time domain, a slot includes 6 OFDM symbols, and a sub-frame includes 2 slots.
At least the multicast channel for transmitting multiple MBMS data (Multimedia Broadcast/Multicast Service data, hereinafter referred to as “multicast data”) and the downlink control channel for transmitting control data are allocated to each multicast sub-frame. The multicast data means broadly-defined multicast data indicating data addressed to multiple mobile station devices, which is a collective term indicating broadcast data addressed to an unspecified number of mobile station devices and narrowly-defined multicast data addressed to a specified number of mobile station devices. Hereinafter, simply-called multicast data indicates the broadly-defined multicast data. The downlink pilot channel used for channel estimation of the multicast channel and the downlink control channel is not shown in FIG. 17, and allocation thereof will be explained later. FIG. 17 shows a case where the downlink control channels are allocated to the first and second OFDM symbols counted from the starting position of the sub-frame, and the multicast channels are allocated to other OFDM symbols. However, the number of OFDM symbols, to which the downlink control channels are allocated, varies in units of sub-frames.
The number of OFDM symbols included in the multicast sub-frame is smaller than that of OFDM symbols included in the unicast sub-frame. However, the length of the OFDM symbol to which the multicast channels are allocated is larger than the length of an OFDM symbol in the unicast sub-frame. Consequently, the time length of a slot in the multicast sub-frame is equal to that of a slot in the unicast sub-frame. However, the length of the OFDM symbols in the multicast sub-frame, to which the downlink control channels (units hatched with diagonal lines) are allocated, is equal to the length of the OFDM symbols in the unicast sub-frame, to which the downlink control channels are allocated. To make the time length of the multicast sub-frame equal to that of the unicast sub-frame, extra samples (densely-hatched units) are allocated in the multicast sub-frame between the OFDM symbols for the downlink control channels and the OFDM symbols for the multicast channels. For example, “0” may be allocated as the extra sample.
Although not shown in FIG. 17, the control format indicator channel, which indicates the number of OFDM symbols forming the downlink control channels, is allocated to a predetermined frequency position of the first OFDM symbol. The downlink control channel is allocated to only the first OFDM symbol in one case, to the first and second OFDM symbols in another case, or the like.
Different from the unicast sub-frame, the downlink control channel is not allocated to the third OFDM symbol in the multicast sub-frame.
Similarly, although not shown in FIG. 17, the downlink HARQ indicator channel is allocated to an OFDM symbol to which the downlink control channels are allocated. In other words, the downlink HARQ indicator channel is frequency-multiplexed with the downlink control channel.
The downlink control channel and the multicast channel are not allocated to the same OFDM symbol. Uplink radio resource assignment information, transmit power command information, and the like are allocated to the downlink control channel in the multicast sub-frame. Downlink radio resource assignment information is not allocated to the downlink control channel in the multicast sub-frame. The details of information allocated to the downlink control channel will be explained later.
<Pilot Channel of Multicast Sub-Frame>
FIG. 18 illustrates allocation of the downlink pilot channels included in one PRB pair in the E-UTRA downlink multicast sub-frame (section 6.10.2 of Non-Patent Document 1). The horizontal and vertical axes shown in FIG. 18 denote time and frequency axes, respectively. A case where the base station device has five transmit antennas (a transmit antenna 1, a transmit antenna 2, a transmit antenna 3, a transmit antenna 4, and a transmit antenna 5) is explained here. A resource element assigned reference numeral R1 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 1. A resource element assigned reference numeral R2 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 2. A resource element assigned reference numeral R3 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 3. A resource element assigned reference numeral R4 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 4. A resource element assigned reference numeral R5 denotes a resource element of the downlink pilot channel to be transmitted from the transmit antenna 5.
The resource elements R1, R2, R3, and R4 are allocated to OFDM symbols forming the downlink control channels. Allocation of the resource elements R1, R2, R3, and R4 is the same as that in the case of the unicast sub-frame. The resource elements R1, R2, R3, and R4 are used for channel compensation on the downlink control channels. The resource element R5 is allocated to OFDM symbols forming the multicast channels, and is used for channel compensation on the multicast channels.
In the case of FIG. 18, the downlink control channels are transmitted using the transmit antennas 1 to 4, and therefore the resource elements R1, R2, R3, and R4 are necessary to perform channel compensation on the downlink control channels. For this reason, the downlink control channels are always allocated to both first and second OFDM symbols.
When the base station device has three transmit antennas, two antennas are used for transmitting the downlink control channels, and the remaining one antenna is used for transmitting the multicast channels. Thus, when the downlink control channels are transmitted from two transmit antennas, the downlink control channels are transmitted on the resource elements R3 and R4 in the second OFDM symbol.
<Multicast>
Multimedia Broadcast/Multicast Service (hereinafter, referred to as “multicast”), in which the base station device transmits data to an unspecified number of mobile station devices, has been proposed in E-UTRA (section 15 of Non-Patent Document 2).
Additionally, single-cell transmission for one base station device to transmit data to an unspecified number of mobile station devices, and a multi-cell transmission for multiple synchronized base station devices to simultaneously transmit the same data to an unspecified number of mobile station devices have been proposed as the multicast services. The multi-cell transmission has the following characteristics.
(1) An MBSFN area, in which multiple base stations are synchronized to simultaneously perform multicast (or broadcast) using the same frequency, is formed (hereinafter, referred to as “multicast area”).
(2) Multiple base station devices in the multicast area simultaneously transmit the same multicast data to an unspecified number of mobile station devices.
(3) The mobile station device can combine the multicast data simultaneously transmitted from the base station devices.
(4) The multicast data is transmitted on a multicast channel in a multicast sub-frame.
(5) Each base station device transmits the multicast channel from one antenna.
The single-cell transmission has little relation to the present invention, and therefore explanations thereof are omitted here.
<Multicast-Dedicated Cell and Multicast/Unicast-Mixed Cell>
Regarding the base station device that performs the multi-cell transmission, there are a cell where the base station device transmits only multicast sub-frames using a multicast-dedicated frequency band (MBMS dedicated cell) and a cell where the base station device time-multiplexes the multicast sub-frame and the unicast sub-frame and performs transmission (MBMS/unicast mixed cell, hereinafter referred to as “multicast/unicast mixed cell”) (section 15.2 of Non-Patent Document 2).
FIG. 19 illustrates a schematic structure of a radio frame for the multicast/unicast mixed cell where the multi-cell transmission is performed. The horizontal and vertical axes shown in FIG. 19 denote time and frequency axes. The first, fourth to sixth, and eighth sub-frames are unicast sub-frames, and the remaining sub-frames are multicast sub-frames. The radio frame of the multicast/unicast mixed cell where the multi-cell transmission is performed has the following characteristics.
(1) The multicast sub-frame and the unicast sub-frame are time-multiplexed.
(2) Multicast data are transmitted on a multicast channel in a multicast sub-frame.
(3) Information data and system information are transmitted on a unicast sub-frame, the information data are transmitted on the downlink shared data channel, and the system information is transmitted on the downlink shared data channel and the broad channel.
(4) The first and sixth sub-frames in the radio frame are always unicast sub-frames, and at least the synchronization channel is transmitted thereon.
The base station device, which transmits only multicast sub-frames using the multicast-dedicated frequency band, has little relation to the present invention, and therefore explanations thereof are omitted here.
<Multicast Sub-Frame Allocation Pattern>
Regarding the base station device performing the multi-cell transmission, sub-frame allocation information for reserving multicast sub-frames, i.e., information for specifying sub-frames to which multicast sub-frames can be allocated (MSAP: MBSFN sub-frame allocation pattern, hereinafter referred to as “multicast sub-frame allocation pattern,” which is also referred to by the 3GPP as “MBSC: MBSFN sub-frame configuration” or “MBSFN sub-frame allocation signaling”) is transmitted by system information on the downlink shared data channel (Non-Patent Document 3).
FIG. 20 illustrates a multicast sub-frame allocation pattern for the multicast/unicast mixed cell in which the multi-cell transmission is performed. The horizontal and vertical axes shown in FIG. 20 denote time and frequency axes, respectively. The multicast sub-frame allocation pattern indicates an allocation of sub-frames reserved for multicast sub-frames in a period. If the multicast sub-frame allocation pattern is not changed in the next period, the same sub-frames are reserved as the multicast sub-frames in the next period of the multicast sub-frame allocation pattern. A period of the multicast sub-frame allocation pattern has not been determined in E-UTRA. However, it has been determined to decide one value from 40 ms to 320 ms (from 40 sub-frames to 320 sub-frames where 1 sub-frame=1 ms) (Non-Patent Document 4).
For example, when a period of the multicast sub-frame allocation pattern is 80 ms (80 sub-frames), 64 bits are required to express the multicast sub-frame allocation pattern by a bit map method (which may be bits that are 16 bits less than 80 bits since the first and sixth sub-frames in the radio frame (=10 sub-frames) are fixed as the unicast sub-frames).
<Dynamic Scheduling Information>
FIG. 21 illustrates information concerning sub-frames on which multicast data allocated to the multicast channels are transmitted, among sub-frames specified by the multicast sub-frame allocation pattern transmitted by the base station performing multi-cell transmission (hereinafter, referred to as “dynamic scheduling information”). The horizontal and vertical axes shown in FIG. 21 denote time and frequency axes, respectively. For simplification of explanations, only the multicast channels to which dynamic scheduling information and multicast data are allocated are shown, and other channels such as the downlink control channels and the downlink shared data channels are not shown. The dynamic scheduling information is denoted as a rectangle that is hatched with diagonal lines. The multicast data is denoted as a rectangle that is not hatched.
In FIG. 21, the dynamic scheduling information indicates to which sub-frames multicast data 1 to 5 are allocated. The dynamic scheduling information is multiplexed with multicast data 1 in one sub-frame.
The dynamic scheduling information has the following characteristics (Non-Patent Document 5).
(1) The dynamic scheduling information indicates a sub-frame to which one or multiple multicast data are allocated.
(2) The dynamic scheduling information may be multiplexed with multicast data in a sub-frame.
(3) Multiple dynamic scheduling information pieces may be included in a period of the multicast sub-frame allocation pattern.
<Reuse of Multicast Sub-Frame Allocatable Sub-Frame (MBSFN Sub-Frame) as Unicast Sub-Frame>
In the multicast/unicast mixed cell where multi-cell transmission is performed, when the amount of multicast data is smaller than the amount of data that can be multicast with the applied multicast sub-frame allocation pattern, such as when the base station device loses part of multicast data to be transmitted on the multicast channel, it has been considered that a sub-frame affected by the smaller amount of data, which is included in multicast sub-frame allocatable sub-frames specified by the multicast sub-frame allocation pattern, is not used for transmitting multicast data, but is used as the unicast sub-frame.
Additionally, a method has been considered in which the mobile station device detects or is informed that multicast data is not transmitted on the sub-frame indicated as multicast sub-frame allocatable by the multicast sub-frame allocation pattern (section 15.3.3 of Non-Patent Document 2).
<DCI (Downlink Control Information) Format>
Multiple control data pieces are allocated to the downlink control channel. There are at least three types of control data pieces to be allocated to the downlink control channel, which are the following.
(1) Radio resource assignment control data on the downlink shared data channel for one mobile station device (hereinafter, referred to as “downlink radio resource assignment information”)
(2) Radio resource assignment control data on the uplink shared data channel for one mobile station device (hereinafter, referred to as “uplink radio resource assignment information”)
(3) Control data including a set of transmit power control commands on the uplink shared data channel and the uplink control channel (hereinafter, referred to as “transmit power commands”) for one mobile station device (hereinafter, referred to as “transmit power command information”) (section 5.3.3. of Non-Patent Document 6).
<DL (Downlink) Radio Resource Assignment Information>
The downlink radio resource assignment information includes at least one set of radio resource assignment information on the downlink shared data channel, a mobile station identifier, a modulation scheme, an encoding rate, a retransmission parameter, and a transmit power command on the uplink control channel. The downlink radio resource assignment information is grouped into the following three groups according to purposes.
(1) Downlink radio resource assignment information for single input multiple output (hereinafter, “SIMO”), of which the radio resource assignment information on the downlink shared data channel (hereinafter, referred to as “downlink radio resource assignment information 1”) is the smallest in size
(2) Downlink radio resource assignment information for SIMO, of which the radio resource assignment information on the downlink shared data channel is larger in size than the downlink radio resource assignment information 1 (hereinafter, referred to as “downlink radio resource assignment information 2”)
(3) Downlink radio resource assignment information for multiple input multiple output (hereinafter, “MIMO”) including two sets of modulation schemes, encoding rates, and retransmission parameters, of which the radio resource assignment information on the downlink shared data channel is the same in size as the downlink radio resource assignment information 2 (hereinafter, referred to as “downlink radio resource assignment information 3”)
The bit lengths (sizes) of the three downlink radio resource assignment information pieces differ from one another. Since the downlink shared data channel is not allocated to the multicast sub-frame, the downlink radio resource assignment information is not allocated to the downlink control channel in the multicast sub-frame. The transmit power command included in the downlink radio resource assignment information is a transmit power command on the uplink control channel used for transmitting a reception response signal in response to the downlink shared data channel.
<UL (Uplink) Radio Resource Assignment Information>
The uplink radio resource assignment information includes a mobile station identifier, uplink radio resource assignment information, a modulation scheme, an encoding rate, a retransmission parameter, and the like. When an uplink system bandwidth is equal to a downlink system bandwidth, the bit length (size) of the uplink radio resource assignment information is equal to the bit length (size) of the downlink radio resource assignment information 1.
<Transmit Power Control (TPC)>
The transmit power command information includes a transmit power command to multiple mobile station devices and a mobile station group identifier. The bit length (size) of the transmit power command information equals that of the uplink radio resource assignment information.
<Coding>
FIG. 22 is a flowchart illustrating an example procedure of coding control data to be allocated to the downlink control channel (section 3.3 of Non-Patent Document 6). First, control data received from the controller is multiplexed with an error detection code. The error detection code is generated from control data using a predetermined generating polynomial. Then, the control data multiplexed with the error detection code is convolutionally-coded.
Then, the convolutionally-coded control data is rate-matched, and then outputted to the QPSK (Quadrature Phase Shift Keying) modulator. The details of rate matching will be explained later.
Then, the rate-matched control data is QPSK-modulated, and then is mapped to resource elements of the downlink control channels. A combination of resource elements of the downlink control channels to which the control data are mapped is limited by the size of the QPSK-modulated control data. When the base station device transmits the downlink control channel using the transmit diversity, a transmit diversity process is performed after the QPSK modulation, and then a mapping to resource elements of the downlink control channels is performed.
<Rate Matching>
Rate matching is to change the encoding rate by a repetition process or a puncture process on the convolutionally-coded control data in order to make the size of the convolutionally-coded control data equal to the size of the physical resource of the downlink control channel to which the control data is mapped.
As the sizes of the rate-matched control data, four sizes are considered in E-UTRA. For example, rate matching is performed so as to make the sizes equal to 36 resource elements, 72 resource elements, 144 resource elements, and 288 resource elements after the QPSK modulation is performed.
Patterns for the repetition process or the puncture process, which adjusts the different-sized control data to different-sized physical resources, differ. In other words, different rate matching patterns are used for different-sized control data, such as the downlink radio resource assignment information 2 and the uplink radio resource assignment information.
When the encoding rate is changed such that the same-sized control data before rate matching are changed to different-sized control data after the rate matching, different rate matching patterns are used.
<Blind Decoding>
FIG. 23 is a flowchart illustrating an example procedure of decoding control data to be allocated to the downlink control channel. For each sub-frame, the mobile station device monitors whether or not control data addressed to the mobile station device is allocated to the downlink control channel. However, the mobile station device has no information about how many control data pieces of what item addressed to the mobile station device are present, to what size of resource elements the rate matching is performed, and to which resource elements the control data pieces are mapped. For this reason, blind decoding is performed in which decoding processes are performed for all possible combinations of resource elements and rate matching.
Specifically, the mobile station device QPSK-demodulates all the resource elements forming the downlink control channels first (S1). Then, the mobile station device selects one possible combination of the number and allocation of resource elements to which control data are mapped (S2). Then, the mobile station device selects one of the possible sizes of the control data before rate matching, and then performs a reverse process to the rate matching (hereinafter, referred to as “rate dematching”), which is determined based on the selected size of the control data and the number of resource elements (S3).
Next, the mobile station device convolutionally-decodes the rate-dematched control data (S4), and then performs error detection using an error detection code (S5). Here, an error detection code, such that the calculation result of the error detection becomes the identifying number of the mobile station device to which the control data is addressed, is used.
If no error is detected after the convolutional decoding, in other words, if the calculation result of the error detection becomes the identifying number of the mobile station device (S6: NO), the mobile station device recognizes that the control data is the control data addressed to the mobile station device. Further, the mobile station device confirms the structure of the control data, and thereby recognizes whether the control data is the uplink radio resource assignment information, the downlink radio resource assignment information, or the transmit power command information (S7). If all pieces of the uplink radio resource assignment information, the downlink radio resource assignment information, and the transmit power command information are decoded (S8: NO), the mobile station device terminates the decoding process.
If there is undecoded control data among the uplink radio resource assignment information, the downlink radio resource assignment information, and the transmit power command information (S8: YES), the mobile station device sets an untried combination of the number and allocation of resource elements to which control data are mapped, and sets an untried size of the control data before rate matching (S9). Then, the mobile station device repeats the operations from S2 in which a resource element is extracted from the downlink control channel.
If any error is detected in the error detection process in step S5 (S6: YES), and if there are an untried combination of the number and allocation of resource elements to which the control data are mapped and an untried size of the control data before rate matching (S10: YES), the mobile station device sets these items (S9). Then, the mobile station device repeats the operations from step S2 in which a resource element is extracted from the downlink control channel.
If the control data decoding process is performed for all the combinations of the numbers and allocations of resource elements to which control data are mapped and for all the sizes of the control data before the rate matching (S10: NO), the mobile station device terminates the decoding process.
When the base station device transmits the downlink control channel using the transmit diversity, the QPSK demodulation in step S1 is performed after a transmit diversity combining process is performed.